OPERATION

The Camshaft Position Sensor (CMP) sensor on the 3.7L (3) contains a hall effect device referred to as a sync signal generator. A rotating target wheel (tonewheel) (4) for the CMP is located at the front of the camshaft for the right cylinder head (2). This sync signal generator detects notches (1) located on a tonewheel. As the tonewheel rotates, the notches pass through the sync signal generator. The signal from the CMP sensor is used in conjunction with the Crankshaft Position Sensor (CKP) to differentiate between fuel injection and spark events. It is also used to synchronize the fuel injectors with their respective cylinders.

When the leading edge of the tonewheel notch enters the tip of the CMP, the interruption of magnetic field causes the voltage to switch high, resulting in a sync signal of approximately 5 volts.

When the trailing edge of the tonewheel notch leaves the tip of the CMP, the change of the magnetic field causes the sync signal voltage to switch low to 0 volts.

2.8L TURBODIESEL

The camshaft position (CMP) sensor is a hall effect switch. A tooth made of a ferromagnetic material is attached to the camshaft. When this tooth passes the CMP sensor an electronic signal is created. This signal is then sent to the engine control module (ECM). This signal is used by the ECM to determine TDC and which cylinder has just entered its compression phase.